are you using my exact code ?
there are many changes from your orig code including swapping over the scl/sda pins to suit my dev board

i doubt the pullup resistors are needed most modules have then already installed


change
COM = $40 : GOSUB SEND_COMMAND ' set start line address
to
COM = $67 : GOSUB SEND_COMMAND ' set start line address
it looks like display is mapped onto last 5 pages of ram array